Multiple tubing string support and safety valve installation



J. S. PAGE March 25, 1969 MULTIPLE TUBING STRING SUPPORT AND SAFETYVALVE INSTALLATION e s T M Na w M M W 4 m 0 M W9 J3 m a 22 T A} a Ma wmy J. S. PAGE March 25, 1969 MULTIPLE TUBING STRING SUPPORT AND SAFETYVALVE INSTALLATION Sheet 2 of 2 Filed April 5, 1967 J'uvsuroe Liou/v $50 PAGE firroeNe-s s.

United States atent 3,434,535 MULTIPLE TUBING STRING SUPPORT AND SAFETYVALVE INSTALLATION John S. Page, Lakewood, Calif.; Eulah N. Page,executrix of the will of said John S. Page, deceased, and sole heir ofthe estate of said John S. Page, assignor, by mesne assignments, to CookTesting C0., Long Beach, Calif., a corporation of Nevada Filed Apr. 3,1967, Ser. No. 627,893 Int. Cl. E21b 43/12 US. Cl. 166-72 7 ClaimsABSTRACT OF THE DISCLOSURE The disclosure concerns installation in awell fluid pressurized tubing string of a control fluid pressureresponsive sub-surface safety valve, without killing the well, and insuch manner that the sub-surface string will not be disturbed despitegreat damage to the well head.

Background of the invention This invention relates generally to wellprotection and operation. More specifically, the invention concernsinstallation in a pressurized well tubing string and operation of acontrol fluid pressure responsive sub-surface safety valve.

In certain oil and gas producing regions it is desirable to installsub-surface safety valves in wells, as for example land wells, which arealready drilled and in production. Such installation secures the wellsagainst possible sabotage such as dynamiting of the well head, for insuch event the safety valve will automatically close and shut in thewell at a sub-surface location below the explosive blast. One method ofinstallation involves injection of mud into the well and at highpressure to kill the well in order to allow safety valve connection inthe string. However, it is a known fact that certain wells in thoseareas, as for example North Africa, are characterized by a type ofproducing formation which can be greatly damaged by such mud injection.Previous practice has shown that such wells, if killed in this manner,will not come back to their normal flowing stage.

Summary of the invention It is a major object of the present inventionto provide unusually advantageous method and apparatus for installationof safety valves in well tubing strings without killing the wells withmud injection. Basically, and in its method aspects, the inventioninvolves steps that include lowering a plug in the well tubing stringfor plugging it at a first location spaced below the top of the string;connecting a control valve in the string at a second location spacedabove the first location, which step is made possible by the initialplugging step; also connecting concentric tubing strings in series withthe well tubing string and above the valve to establish one path forcontrol pressure communication to the valve via one of the concentricstrings and another path for well production fluid flow upwardly fromthe tubing string below the valve to another of the concentric stringsand via the valve; and thereafter elevating the plug through the valveand the other concentric string for unplugging well production fluidflow via the other path. Typically the control valve is lowered to asub-surface location as a result of connecting the concentric stringsections into the string, whereby the valve is not only inserted in thestring but also it is lowered to a position below potential blastefiects, where the valve may automatically shut off should controlpressure be sharply reduced as for example due to such a blast.

Additional steps of the novel method include sealing oif between thestring and well bore during connection of the control valve in thestring, one such sealing method advantageously including installing atthe well head a pressure lock between the tubing and the well bore andelevating the top of the string through the lock for connection of thevalve to the string at the exterior of the lock; connecting a settablesupport to the string proximate the valve location and prior toconcentric string connection to the string, lowering the support andvalve in the well during concentric string connection, and setting thesupport at a sub-surface location in the well to support the string;installing at the well head a pressure lock between the tubing and thewell bore and lowering the valve and support through that lock;connecting a well packer in the string to be lowered with the support,and setting the packer; and sealing off between each of the concentricstrings and the well bore, proximate the concentric string upperterminals, to maintain separation of the aforementioned flow paths atthe well head.

In its basic apparatus aspects, the installed assembly includes tubingstring means installed in the well and sub-surface valve means connectedin the string, the latter including a lower tubing string extendingbelow the valve means for flowing production fluid upwardly to the valvemeans, and inner and outer generally concentric upper tubing stringsextending upwardly between the valve means and the well head, the valvemeans being responsive to control fluid pressure introduced into one ofthe upper tubing strings to control the upward flow of production fluidfrom the lower string to the other of the upper concentric strings;subsurface support means supporting the string means in the well; andstructure at the well head to supply control fluid pressure to the oneupper tubing string and to receive flow of well production fluid fromthe other of the upper tubing strings, that structure including a wellbore extension receiving the upper tubing strings with the inner stringprojecting above the upper terminal of the outer string, first sealingmeans sealing off between the inner string and the bore extension abovethe upper terminal of the outer string, and second sealing means sealingoff between the outer tubing string and the bore extension and spacedbelow the first sealing means. Typically, and as will be seen, the firstand second sealing means may comprise spools respectively mounted on theinner and outer tubing strings.

Additional structural aspects of the invention include the freedom ofthe tubing string means from vertical support at the well head, wherebyin the vent of upward dynamiting of the well head the tubing will not becarried with it; the location of the sub-surface string support means onthe lower string in the well; the provision of means packing off betweenthe lower string and the well bore, and which cannot be disturbed in theevent of blasting of the well head since the well head equipment doesnot support the string; and the provision of a first pipe outside thebore extension at the well head to communicate with the upper interiorof the inner tubing string, and a second pipe outside the bore extensionat the well head to communicate with the upper interior of the outertubing string, one pipe supplying control fluid for operating thesub-surface valve and the other pipe receiving well production fluidflow.

These and other objects and advantages of the invention, as well as thedetails of illustrative embodiments, will be more fully understood fromthe following detailed description of the drawings, in which:

Brief description of the drawing FIG. 1 is a vertical elevation taken insection to show the assembly installed in a well;

FIG. 2 is an enlarged vertical section taken on line 2-2 of FIG. 1,showing a typical sub-surface valve in open state;

FIG. 3 is an enlarged view similar to FIG. 2 but showing the valve inclosed state;

FIG. 4 is a section taken on line 44 of FIG. 3;

FIGS. 5 and *6 are vertical sections illustrating steps in the method ofsub-surface valve installation;

FIG. 6a is a vertical elevation illustrating another step; and

FIG. 7 is a vertical section showing plug construction.

Referring first to FIGS. 1 and 2, a well bore 10 is shown as cased at 11with tubing string means 12 installed in the well. The string meansincludes a lower tubing string 13 extending below valve means 14connected in the tubing string, the latter also inner and outergenerally concentric upper tubing strings 15 and 16 extending upwardlybetween the valve means and the well head.

Generally speaking, the valve means 14 is responsive to control fluidpressure introduced into one of the upper tubing strings 15 and 16 tocontrol the upward flow of production fluid from the lower string 13 tothe other of the upper tubing strings. In the example shown, the valvemeans is responsive to control fluid pressure introduced into theinterior 17 of the outer one 16 of the upper strings, thereby to controlproduction fluid flow from the lower string into the interior 18 of theinner one of the upper tubing strings.

The illustrated valve means includes a sub body 19 having interiorlythreaded pin and box ends 20 and 21 respectively connected to the lowerand upper strings 13 and 15. The body itself includes interconnectedtubular sections 19a, 19b and 190, and the outer concentric string 16 isconnected to the body at 22. Control pressure is applied from theinterior 17 of the outer string, and

via side port 23 in the body section 1%, to a chamber 24 formed by thebody and an axially movable valve sleeve 25. Such pressure exerted onpiston surface 26 tends to urge the sleeve downwardly in a direction todisplace the sleeve skirt 27 from closed position as seen in FIG. 3 toopen position seen in FIG. 2. In FIG. 3, the skirt closes off access ofproduction fluid flow to a by-pass channel 29 via an entrance side portat 30, whereas in FIG. 2 that port is open to pass the flow upwardly inthe channel 29, the flow re-entering the interior of the sub body at 31above a plug 32, for upward flow in inner string 15.

Plug 32 seals at 33 against the bore 34 of the cylindrical insert 35suitably attached to the sub as by circularly spaced vertical webs 36.In this regard, the plug may be introduced to the inner string 15 viathe lubrication unit '80 (to be described later) and lowered by wireline attached to plug nipple 37, for releasable attachment to the valveinterior. Such attachment may be effected by reception of lugs 38 (oncollet spring fingers 39) into the annular groove 40 formed by theinsert 35. The plug is retrievable as by connection of a wire linelowered cup onto the spring finger serrated terminals 41, to collapsethe fingers inwardly releasing the lugs from groove 40.

A helical spring 42 retained by sub section 190 urges the valve sleeveupwardly at 43, tending to maintain the port closed. Such closing actioncan be overcome by exertion of suflicient control fluid pressuredownwardly in the outer concentric string 16, to open the valve;conversely, the valve can be closed by reducing the control fluidpressure exerted at 26.

It is an important feature of the invent-ion that the string assembly asdescribed is supported in the well by sub-surface support means, wherebysevere damage to the well head (as by explosives) will not result indisruption of string support in the well. In this regard, FIG. 1 showsthe provision of sub-surface support means below the valve 14 and in theform of slips 47 which are set in response to fluid pressure exertion inthe lower string. The pressure is applied to a suitable piston urgingthe slips axially against a cam surface which tapers to wedge the slipsoutwardly and against the bore 48 of the casing 11. Such a support meansas described is disclosed in John S. Page application for US. LettersPatent Ser. No. 520,470, filed Jan. 13, 1966.

The objective of non-disturbance of the string, despite great damage tothe well head, is further enhanced by reason of th characteristic thatthe tubing string means is free of vertical support at the well head. Inthe example shown, this characteristic is found in the structure at thewell head by which control fluid pressure is applied to one upper tubingstring (as for example string 16) and by which production fluid isreceived from the other tubing string (as for example string 15). Suchstructure includes a well bore extension, as for example casing section50 of the casing head 51, which receives the tubing strings 15 and 16with the inner string projecting at 15a above the upper terminal 16a ofthe outer string. First sealing means, as for example first spool 52 onstring terminal 15a, seals olf between the bore 53 and the inner stringupper terminal 15a; likewise, second sealing means, as for examplesecond spool 54 on string terminal 16a, seals oif between the bore 53and the outer string upper terminal 16a. Since the spools are in effectslidable with respect to bore 53, although sealing thereagainst, thecasing head may be blown upwardly from the floor 56 and off the spools,without pulling the strings along to any extent.

The above mentioned structure may also be considered to include a firstpipe 61 outside the well bore extension formed by the casing section 50and communicating via a side port in the section 50 with the upperinterior of the inner tubing string 15; similarly, a second pipe 62communicates with the interior of the outer tubing string 16, spool 52sealing off communication of the spaces above and below it and withinthe casing section 50. Pipe 62 supplies control fluid pressure from asource 63, and pipe 61 receives flow of production fluid. Valves 64 and65 in pipes 61 and 62 are used for flow control. Note that the valvesleeve 25 will be closed to FIG. 3 position, by reduction of controlpressure applied at chamber 24, in the event of rupture of line '62, therating of spring 42 and the depth of the valve in the well being such asto serve this function.

To complete the description of FIG. 1, the tree at the well headincludes casing head sections 66 and 67, the latter having branches 68and 69 controlled by valves 70 and 71, for controlling fluid flow to andfrom the annulus 72, if desired. The casing head is capped at 73, as bysection 74 mounting a shut-off valve 75. Finally, the lower string 13carries means packing off between that string and the well bore 42. Thepacker 77 of FIG. 1 serves this function, and may have the constructionas shown and described in the Page application Ser. No. 520,470 referredto above. As there described, the packer 77 is expanded against bore 48in response to fluid pressure application in the tubing 13.

A further and important aspect of the invention has to do withinstalling the FIG. 1 equipment in a flowing well, without use of mudwhich might irrevocably kill the well or reduce its production tosubstantial degree. Such beneficial installation may be had inaccordance with the following teachings, an understanding of which willbe helpfully gained by reference to and study of FIGS. 5 and 6.

The method involves lowering a retrievable plug in the original string13, which extends to the well head, as by Wire line 86, for plugging thestring at a first location spaced below the top of the string. Forexample, the plug may be lowered to the location of a tubing coupling87, for packing off proximate the interior recess provided by thecoupling. The plug 85 may be of the construction as shown in FIG. 7herein, having a tubular body supported by a collet 121 which engagesbody shoulder 120a in running position. The collet has spring fingers122 with latch dogs 123 urged outwardly to engage the tubing bore 124during running. A ram 125, supported by wire line 86, urges the plugdownwardly in the string to desired depth, as by engagement with thetops 127 of the fingers, the ram also including a rod 128 of a length tohold the ball 129 in body 120 011 annular seat 130, during running. Thisallows the plug to pass well fluid relatively upwardly therethrough,during running.

Upon arrival of the plug at desired depth, the latch dogs 123 snapoutwardly into the groove 131 inwardly of collar 87, to locate the plugand to resist its upward displacement. Also, ram 125 is retrieved. Aspring 132 urges ball 129 against seat 130, and shut in well pressureurges body 120 upwardly relative to the collet, from a lower or extendedposit-ion to the collapsed condition shown, in which fingers 122 areblocked against inward retraction. Shoulder 134 on the body thenpressurizes the elastomeric seal ring 135 toward metal ring 136 retainedbeneath the collet. Seal 135 then expands and packs off between the body120 and the bore 124. Retrieval of the plug is accomplished by wire linelowering of a retrieval cup 140 acting to collapse finger terminals 141inwardly and to grip their serrations 142, followed by lifting of thecup and the plug. Such plug manipulation is aflorded by first attachingthe lubricator 80 to the top of the flange 87 on the tree 51. The plugis lowered past open valve 88 and into lubricator tubular body 89, valve75 being closed; thereafter, valve 75 is opened and valve 88 closed,enabling lowering of the plug by wire line into plugging position in thetubing 13. A top packing for the wire line is contained at 89a.Thereafter, the lubrication is removed, and the tree 51 is removed offflange 90. Note that the string is supported by a ring 91 attached tothe tubing and seated at 92 in the casing head section 67.

The larger lubricator 93 together with upper and lower rams 94 and 95 isnext installed on flange 90. The rams are of known gate type, operableto open and close the passages in tubular bodies 94a and 95a. Next, aspare joint of tubing 13a is hoisted as at 96 and the pin end thereof islowered through the lubricator and open rams, and threaded into the ring91 as seen in FIG. 6a (tubing 13 being plugged off as described above).The rams are then closed about the adding tubing 13a and the lubricator93 is pressured to equal well pressure in the annulus 72, as viapressure line 97. Lower ram 95 is then opened, and the string is hoistedto ele vate ring 91 to a position in the lubricator and between therams.

Thereafter, the lower rams 95 are closed about the hoisted tubing 13 andthe upper rams are opened away from tubing 13a. The tubing as againelevated to raise the ring 91 clear of the top of the ram 94, followingwhich the ring 91 and tubing 13a are removed from tubing 13.

The unit embodying the packer 77 and slips 47 is next attached to theexposed tubing. These elements are then lowered through the lubricator,with opening and closing of rams 94 and 95 to maintain lock action.Thereafter, the valve 14 is added and concentric strings 15 and 16attached and lowered through the lubricator and rams to desired depth,although a depth of 100 feet for the valve 14 would normally not beexceeded, or needed to protect against explosive damage. The packer isthen extended or set, at such time that the upper terminals 15a and 16aof the concentric upper strings terminate in the casing as seen in FIG.1, and as also seen in broken lines in FIG. 6. Also, the slips 47 areset. As explained in the referred to Page application Serial No.520,470, fluid pressure may be exerted from the surface, andcommunicated via strings 15 and 13, for setting of the packer and slips.Well pressure exerted upwardly against plug bore 129 is suflicient toprevent opening of the ball off seat 130.

The annulus is now shut in by the packer, and the tubing 13 stillremains plugged at collar 87, so the lubricator 93 and rams 94 and 95can then be removed. Spools 52 and 54 are attached, in the position asseen in FIG. 1, and the stacked tree elements 50, 74, and 89 attached tothe casing head section 67, as seen in FIG. 1. The auxiliary equipment63 including booster pump and pilot valve are attached along with piping61 and 62.

Finally, the retrieval cup is lowered by wire line 86 to latch onto theplug terminals 141, the line is pulled removing the plug from tubing 13,and the valve plug 33 previously described is lowered and installed. Thewireline tools are then removed, and the installation is completed inthe configuration described in FIG. 1.

I claim:

1. In a well assemby,

tubing string means installed in the well and sub-surface valve meansconnected in said string means, said string means including a lowertubing string extending below the valve means for flowing productionfluid upwardly to the valve means and inner and outer generallyconcentric upper tubing strings extending upwardly between the valvemeans and the well held, the valve means being responsive to controlfluid pressure in one of said upper tubing strings to control the upwardflow of production fluid from the lower string to the other of saidupper tubing strings,

sub-surface support means supporting said string means in the well,

and structure at the well head to supply control fluid pressure to saidone upper tubing string and to receive flow of well production fluidfrom the other of said upper tubing strings, said structure including awell bore extension receiving said upper tubing strings with the innerstring projecting above the upper terminal of said outer tubing string,first sealing means sealing oft between the inner string and the boreextension above said upper terminal of said outer string, and secondsealing means sealing off between the outer tubing string and said boreextension and spaced below said first sealing means.

2. The assembly of claim 1, wherein said first and second sealing meanscomprise first and second spools respectively mounted on the inner andouter tubing strings.

3. The assembly of claim 2, wherein said structure includes a first pipeoutside the bore extension communicating via said extension with theupper interior of the inner tubing string, and a second pipe outside thebore extension communicating via said extension with the upper interiorof the outer tubing string, one of said pipes supplying said controlfluid pressure and the other of said pipes receiving said flow ofproduction fluid.

4. The assembly of claim 1, in which the tubing string means is free ofvertical support at the well head.

5. The assembly of claim 4, in which said sub-surface string supportmeans is on said lower string in the well and includes a slip engagedwith the well bore.

6. The assembly of claim 1, including means packing ofl? between saidlower string and the well bore.

7. The assembly of claim 1, wherein said bore extension is defined by acasing head.

References Cited UNITED STATES PATENTS Re. 26,149 1/ 1967 Sizer et a1.166-72 3,065,794 11/1962 Page 166-72 X 3,156,300 11/1964 Page et a].166-72 X 3,351,133 11/1967 Clark et al 166-72 X DAVID H. BROWN, PrimaryExaminer.

U.S. Cl. X.R.

